Marine propulsion system



Feb. 16, 1932. F. HQDGKINSON 1,845,087

MARINE PRoPULsIoN surs'lzml Filed March 8, 1929 2 Sheets-Sheet, 1

A TTORNEY F. HODGKINSON KARINE PROPULSION SYSTEM Feb. 16, 1932.

2 Sheets-Sheet 2 Filed March 8. 1929 `Il S IN VEN TOR r. Hoag ATTORNEY 20 neuvering the ship,

30 disconnected.

s hausted from the engine More particularly,

Patented Feb. 16, 1932 UNITED STATES lPATENT oFElcE VAN 1A MARINE PROPULSION SYSTEM:

Application led March 8, 1929. Serial No. 345,388.

My invention relates to improvements in the application of low-pressure turbines to operate in combination` with reciprocating engines,l particularly where the reciprocating 5 engine 1s required to be reversed such, for

example, as for the propulsion of a ship.

low-pressure turbme operated by mo.-

U tive fluid exhausted from a reciprocating engine, whereby increased efiiciency or increased output, or both, is obtained, is old.

uch low-pressure turbines have been employed for the propulsion of ships; and they f have been connected to propeller shafts independently of the, reciprocating engines or the rotors of the turbines have been connected directly to the engine propeller shafts. j In these cases, it has not been usual to provide the low-pressure turbines with reversingl elements, and it has been the practice when mato provide means for bypassing exhaust steam directly from the reciprocating engine to the condenser, particularly when operating astern. It is also old in the art to provide a reciprocating engine and a turbine coupled by gearing to the same propeller shaft however, in such cases, it has been customary to prov'de a clutch between the turbine and the propeller shaft so that, during astern o eration, the turbine may be arious automatic arrangements have been provided for bringing about the disconnection of the turbine in the event of a reciprocating engine operating in an astern direction.

It is an object of my invention to provide apparatus of this character having a reciprocating engine directly connected to the propeller shaft and a turbine geared to the propeller shaft and operated by steam exwherein the apparatus is somewhat simplified in that a disconnectible clutch is eliminated and the apparatus is, at the same time, capable of being operated with safety.

it is a further object of my invention to provide a marine propulsion organization of the character just referred to with torque-responsive slip coupling means arrangedin the transmission between l the turbine and the propeller shaft, whereby to the turbine. It is,

dangerous stresses in the connecting mechanism and the shafts in the event of the reciprocating engine being quickly stopped or reversed are avoided. Such means also` provide a dampening effect should there be any tendency to torsional vibration of the connecting elements.

With the arrangement referred to, where the turbine is operated by steam exhausted from the reciprocating engine when running ahead and where exhaust steam from the reciprocating engine is cut-off from the turbine and supplied to the condenser when running astern, there is a tendency for the turbine to overheat when operating astern due to the blades of the turbine doing work on the gaseous media within the turbine. Hence, a further object of my invention is to provide means whereby the turbine may be ventilated when the reciprocating engine 1s operated astern.

Also with apparatus of the character referre lto,it is advantageous that as much moisture as the exhaust steam before the latter is supplied therefore, a further object of my invention to incorporate suitable separating means in the connection between the reciprocating engine and the turbine.

These and other objects are effected by m invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. 1 is a plan view of a. marine propulsion organization with parts thereof shown in section and having my improvement applied thereto;

Fig. 2 is a sectional view of the torque-responsive slip coupling employed inthe transmission between the turbine and the propeller shaft;

Fig. 3 is a view somewhat similar to Fig. 1 but showing the torque-responsive slip coupling arranged in an element of the reduction gearing between the turbine and the propeller shaft;

Fig. 4 is a vertical sectional view of one form of feed-water heater which may be arranged in the exhaust connection between possible may be removed from Yao the reciprocating engine andthe turbine for removing moisture from exhaust steam;

Fig. 5 is a vertical sectional view of a modified form of feed water heater;

Fig. 6 is a cross-sectional view taken along the line VI-VI of Fig. 5; and,

Fig. v7 is a detail view showing modified means for the removal of moisture.

Referring now to Fig. 1, I show a reciprocating steam engine 10 directly connected to the main propeller shaft 11. A steam turbine 12 has a connection 13 leading to the condenser 14. Steam exhausted from the reciprocating engine may be supplied either to the turbine or to the condenser.

The reciprocating engine 10 has an exhaust line or connection 15 leading to a heater or separator 16 and the heater or separator has a discharge connection 17 leading to the valve 18, whose casing has ports 19 connected to a passage or conduit 2O leading to the admission space 21 of the turbine 12 and with ports 22 therein communicating with the passage or conduit 23 leading to the condenser 14. The valve 18 may be of any suitable form, for example, I show a piston member 25 ar-l ranged to establish communication of the reciprocating engine exhaust passage either with the turbine or with the condenser. When in one position, the valve member 25-is arranged to cover the ports 19, and, when in its other position, to cover the ports 22. ,The piston valve has passages 26 formed therein so as to permit the passage of exhaust steam to the ports 22 when it is in the position covering the ports 19.

lNhile the valve mechanism just referred to may be operated in any suitable manner, I prefer to use mechanism which is under control of the reversing mechanism of the reciprocating engine. To this end, I show suitable servo-motor means 27 for operating the valve 18, such servo-motor means including an operating piston 28 arranged in the cylinder 29 to which motive fluid is supplied and exhausted by a pilot valve 30, the pilot valve 30 being connected to the reversing lever 31 of theV engine through a connection including a bell crank'lever 32. The arrangement is such that, when the reversing lever of the reciprocating engine 10 occupies the position for astern-operation, the servo-motor 27 is rendered effective to cut-off the supply of exhaust steam in the turbine and to connect it to the condenser.

The reversing lever 31 is connected to and controls the reversing mechanism of the re. ciprocating engine 10, indicated at 31. On the drawing. the i has been shifted from its correct position relative to the engine in order to illustrate its connection with the reversing lever 31. It may be of any conventional construction known in the art.

The reversing lever 31 is moved to the right `reaction type, it has the capacity for pumping. I, therereversing mechanism 31V for ahead operation of the reciprocating engine 10, and to the left for astern operation,

as indicated on the drawings. When the lever 31 is in the right hand position for ahead f operation as shown on the drawings, the pilot valve 30 is in the upper position shown on the drawings, admitting fluid pressure to the lower end of the cylinder 29. 'l` he fluid pressure acts on the piston 28, and the latter holds the valve vmember 25 in the position shown on the drawings, in which the ports 22 leading to the condenser are closed and the ports 19 are open. Vhen the reversing lever 31 is positioned for ahead operation, therefore, the steam exhausted from the engine 10 is conveyed to the turbine 12.

When it is desired to operate the engine 10 in astern direction, the reversing lever 31 is moved to the left, rotating the bell crank lever 32 in counter-clockwise direction and moving the pilot valve 30 downwardly. Fluid pressure is admitted to the upper end of the cylinder 29 to move the piston 28 downwardly to a position in which the ports 19 are closed and the ports 22 are open. During astern operation, therefore, the steam exhausted from the engine is'conveyed directly to the condenser.

In maneuvering, or if astern operation continues for any length of time, there is danger of the turbine overheating owing to the blading doing work on the gaseous or vaporous media therein unless the turbine is ventilated. As the turbine 12 is preferably one of the when it is operated astern,

fore, provide a passage or conduit 33 including a valve 34 leading to the condenser 14 and the valve 34 is connected to the operating mechanism for the switch valve 18 so that it is opened when the passage of exhaust steam from the reciprocating engine to the turbine is interrupted. IVhen this occurs, and with the turbine being operated reversely due to the transmission mechanism, to be hereinafter more specifically described, adequate ventilation is secured, as the turbine 12 operates as a pump to withdraw gaseous media or vapor from the inlet' connection to the condenser and pump such media back through the passage or conduit 33 to the condenser.

'lhe turbine 12 is designed to operate at a higher speed than the propeller shaft 11. Therefore, I provide transmission mechanism 35, including double reduction gearing, for transmitting power from the turbine to the propeller shaft. More particularly, the turbine drives a shaft 86 connected to a pinion 3T meshing with an intermediate gear 38, the latter being directly connected to intermediate pinion portions 39, which mesh with driven gear portions 40 carried by the propeller shaft 11.

With the arrangement just described, it

will be apparent that, unless avoided, dangerous stresses might be set up in the shafts and the connecting gearing incident to quick stopping or reversal of the reciprocating engine. Also, means should be provided to avoid excessive stresses owing to torsional vibrations developed at any time, the result, on the one hand, of uneven crank action of the reciprocating engine, and, on the other hand, of the pendulumic association therewith of the mass of the turbine iotor. Both of these purposes are achieved by the association, with the transmission mechanism for connecting the turbine tothe propeller shaft, of torque-responsive slip coupling means indicated generally at 42. In Fig. l, I show the slip coupling inea-ns .incorporated in the turbine drive shaft 36, and, in Figf3, the slip coupling means 42a is incorporated in one of the gear members of the reduction gear. It will be apparent that, should the transmission means between the turbine and the propeller shaft be subjected to excessive stresses, the coupling means referred to will slip, thereby limiting the attainable stress magnitude.

While any vsuitable torque-responsive slipV coupling means may be employed, in Figs. 2 and 3, l show, by way of example, coupling means which may be satisfactorily employed. In Fig. 2, the shaft 36 includes sections 36a and 365, the section` 36a extending to the turbine and the section 366 extending to the pinion 3T. The section 36bis connected to a housing 43,' and, arranged within the housing 43, there is a multiple disc construction 44 including discs alternately connected to the shaft section 36a and to the housing 43. A

' follower 45 exei ts pressure on the discs, suitable springs 46 being arranged between the housing cover 4T and the follower 45. As

shown, the springs 46 are arranged within suitable chambers 48 and adjustable followers 49 are arranged between the outer ends of said chambers and the outer ends of the springs. By adjusting the followers 49, the springs 46 may bey adjusted in order to provide for slipping of the coupling in response to a predetermined torque'.

In Fig. 3, Ishow a coupling 42a embodied in one of the gear members, for examplekbetween the' uband web construction 5,4 of the driven gear 38'and the shaft 55 connected to the pinion portions 39. In principle, the operation of the coupling shown in Fig. 3 is the same as that shown in Fig. 2for, so far as the operative effect of the coupling is concerned, it may be incorporated any! where in the'transmission between the turbine and the propeller shaft.

As already pointed out, it is desirable to suppl)7 steam to the turbine 12 in as dry a condition as possible. In Fig. 4, I show a feed-water heater, at 16, having an inlet 55, which may be connected to the exhaust pasthe heater and this inlet. being sage 15 of the reciprocating engine, and provided with an outlet 56, which may be connected to the passage 1T leading to the valve 18. Any steam discharge by the reciprocating engine will pass through the inlet into uncondensed steam will pass through the outlet opening 56 to the turbine 12. I have indicated cold feed-water entering the heater at 57 in the general direction of the arrows, the heated water leaving at 58.

The steam on entering this heater has its velocity reduced and comes in contactwith the tubes 59 containing the feed-water, thus precipitating the moisture on the tubes and permitting it vto trickle to the bottom of the heater. Regardless of the amount of surface in the heater, it is impossible for more steam to be condensed therein than that required to bring the feed-water to the same temperature as the steam. However, any steam condensed in the hea-ter and the latent heat thereof used in heating the feed water, is employed more efficiently than by any other known means and more eiiciently than if it passed through the low pressure turbine. It is plain'that, by this disposition of a heater, the steam leaving the outlet 56 and going to the turbine will be nearly dried regardless of the amount of moisture contained in the steam entering the inlet 55 from the reciprocating engine.

A trap is shown at 60 and arranged to drain condensate from the lower portion of the heater and such bined with the feed-water by any suitable or well known means.

In Fig. 5, I show a modified form of heater in which feed-water may enter through the opening 57a. and be discharged through the opening 58a, the heating surface being in the form of bent tubes 59a. In this modification, steam enters the heater from the reciprocating engine through the inlet 55a, arranged eccentrically with respect to the heater shell or tangentially with respect thereto as shown in Fig. 6; and this opening 55a is preferably arranged wholly or partly above the upper portions of the tubes 59a where its flowy is unimpeded by the The tangential arrangement of tubes 59a. the opening 55a produces a rotationof the steam in the space above the tubes 59a, and the centrifugal force imparted to theinoisture brings the same in contact with the heater shell where, because of the viscosity of the moisture, it will adhere. The outlet 56a to the turbine is arranged at the top of the heater.

- In Fig. 7, I show alternative means of separating moisture by means of a special form of piping connection between the reciprocating engine and the transfer or switch valve 18. Steam from the engine enters the bent or looped pipe 62 at 63 and leaves at 64. At

the bottom of the loop portion 65, of the pipe l" drainage may be com-A there is disposed an outlet 6G, whose connection with the loop portion 'is arranged to give opening to the whole ot the lower halt` ot the pipe 62, the connection 66 being arranged to lead moisture and steam to any suitable form of feed-water heater. It should be understood that, if the connection 6G were connected to a trap, for example, the sole purpose of which would be draining of moisture, it would be quite ineffective'in producing separation, but, inasmuch as the connection 66 leads to a heater G7 to which there is considerable iiow not only of moisture but of steam, the velocities therein will entrain the moisture and be much more eiiective in this respect than a trap. Vith this Jform of my invention, the looped conduit 62 provides a direct connection between the engine and the turbine.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

l. In a marine power plant, the combination of a reciprocating steam engine, a propeller shaft directly connected to the engine, a steam turbine, transmission mechanism for connecting the steam turbine to the propeller shaft including a torque responsive slip coupling, a condenser, exhaust conduits between the reciprocating engine and the turbine and between the reciprocating engine and the condenser, valve mechanism or controlling the exhaust connections so that exhaust steam from the reciprocating engine may pass either to the turbine or lvto the condenser, reversing mechanism for the reciprocating engine, means responsive to operation of the reversing mechanism when the reciprocating engine is reversed to operate said valve mechanism to cut oit the connection between the reciprocating engine and the turbine and tol establish the connection between the reciprocating engine andthe condenser, means providing a passage between the admission end of the turbine and the condenser and including a valve, and means responsive to reversing operation of said reciprocating engine to open the last-named valve.

2. In a marine power plant, tion of a reciprocating engine,

the combinaa propeller shaft directly connected to the engine, a,

steam turbine, transmission mechanism for connecting the steam turbine to the propeller shaft, a condenser, exhaust conduits between the reciprocating engine and the turbine and between the reciprocating engine and the condenser, valve mechanism for controlling the exhaust connections so that exhaust steam from the reciprocating engine may pass either to the turbine or to the condenser, operating mechanism for said valve mechanism, means providing a passage between the admission end of the turbine and the condenser, and a valve in said passage connected to the valve operating mechanism and arranged so that it is closed -when the valve mechanism is positioned to pass exhaust steam to the turbine and open when the valve mechanism is positioned to pass exhaust steam to the condenser.

In testimony whereof, I have hereunto subscribed my name this 25th day of February,

FRANCIS HODGKINSON. 

